<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<div>
  <input type="text" name="h" placeholder="身高（米）" v-model="h">
  <input type="text" name="w" placeholder="体重（kg）" v-model="w">
  <input type="button" value="测试" @click="f1()">
  <h2>{{bmi}}</h2>
</div>

<script src="https://cdn.bootcdn.net/ajax/libs/axios/0.21.1/axios.min.js"></script>
 <script src="https://cdn.staticfile.org/vue/2.2.2/vue.min.js"></script>
     <script>
         let v = new Vue({
             el:"body>div",
             data:{
                 h:"",
                 w:"",
                 bmi:""

             },
             methods:{
                 f1(){
                   axios.get("/bmi?h="+v.h+"&w="+v.w+"").then(function (response) {
                     // alert(response.data)
                     v.bmi = response.data
                   })
                 }
             }

         })
     </script>
</body>
</html>